Introduction to Steroids

By Debbie Roes

A number of medications can be used to help manage Feline Inflammatory Bowel Disease (IBD). Corticosteroids, or steroids for short, are typically the key drugs prescribed by veterinarians for this condition. This article covers some basic information about corticosteroids, the various types of steroids, why one type may be used over another, potential side effects, and other important things to know. One of the mainstays of managing feline inflammatory bowel disease is the use of corticosteroids, or steroids for short. While we pet parents would like to avoid giving our cats strong pharmaceuticals, the critical nature of the disease often makes it unmanageable without using steroids to reduce the intestinal inflammation. While cats generally handle these types of drugs much better than dogs or humans, there is still a risk of side effects, most notably diabetes, especially with long-term use.

What are Corticosteroids
Corticosteroids are a class of hormones that are produced in the adrenal glands. They are involved in a wide range of bodily functions, including the stress response, immune system response, control of inflammation, nutrient metabolism, and the maintenance of blood electrolyte levels. Corticosteroid medications mimic the effects of the hormones that are naturally produced by the adrenal glands. When prescribed in doses that exceed the levels that are normally present in the body, corticosteroids suppress inflammation. This can reduce the signs and symptoms of various types of inflammatory conditions, including inflammatory bowel disease. Thus, corticosteroids are a valuable class of medications in the management of Feline IBD.

If your cat had an ultrasound done that highlighted suspected IBD (IBD can only be definitively diagnosed through an intestinal biopsy), you were likely told that intestinal thickening was observed. This is a hallmark of the disease and steroids may be used to decrease this inflammation on either a short or long-term basis.

While some cats’ symptoms can be managed successfully through dietary changes, most will need to remain on these drugs over the long-term to help control inflammation and related symptoms. However, in many cases, the dosage can be reduced over time as the cat’s condition improves. There are several different types of steroids that can be used to help manage Feline IBD. These medications are available in multiple formats, including pills, chewable tablets, compounded liquids, transdermal gels, and injections. The forms available will vary depending upon the type of steroid prescribed. The following are the steroids generally prescribed for Feline IBD.

Prednisolone and Prednisone
Prednisolone and prednisone are the most commonly used steroids for Feline IBD. It is important to understand the difference between these two steroids, as people often get them confused and they are not the same. The primary distinction is that prednisone needs to be converted by the liver (into prednisolone) before it can be utilized by the body. Studies have shown that oral prednisolone has a better bioavailability for the feline patient than oral prednisone, as evidenced by a higher concentration of prednisolone in blood samples when equal amounts of both drugs were given to the same animals. It’s not entirely certain whether this finding resulted from increased gastrointestinal absorption or decreased hepatic (liver) conversion from prednisone to prednisolone, but the bottom line is that prednisolone has been shown to be the superior choice for cats.

Dosages of prednisolone typically start out at a higher level and are gradually tapered down as the cat’s condition stabilizes. While dosing is very individual, it’s common for a 10 pound cat to receive 5 mg. of prednisolone twice per day for the first two weeks and 5 mg. once a day for another two weeks. Then the dosage is often decreased to 5 mg. every other day for four weeks or as needed for maintenance therapy. Higher doses are sometimes used for severe or resistant IBD cases. While side effects can occur in cats that are given steroids, especially for long periods of time, the incidence of these problems is lower than what is seen in either humans or dogs. That said there are issues that may arise in some cats.  Some of these possible side effects include increased hunger, increased thirst and urination, loss of energy, behavior changes, development or worsening of infections (especially of the skin), vomiting or nausea (less common), and in rare instances, personality changes.

The most common mistakes made during treatment are starting off with too low a dose of prednisolone or not giving the drug for a long enough period of time. The inflammation in a cat’s intestinal tract did not develop overnight, so it will also take time to reduce that inflammation. Of course, steroid treatments are often more effective when combined with other adjunct therapies, including food changes, B-12 injections, probiotics, digestive enzymes and oftentimes anti-nausea medication.

Budesonide (Entocort)
Budesonide is an alternate steroid that may also be prescribed by veterinarians for dogs and cats with inflammatory bowel disease. Budesonide was approved for human use by the FDA in 2001 for the treatment of Crohn’s disease and ulcerative colitis, the human forms of inflammatory bowel disease. Budesonide is taken orally and moved along the gastrointestinal tract along with the rest of the intestinal content. Along the way, the inflamed intestinal lining is bathed with corticosteroid treatment, similar to when you rub a cortisone cream on your irritated skin. The budesonide gets absorbed by the cat’s intestines but is then removed almost immediately by the liver in what is termed a “first-pass effect.” In this way, the body at large only sees minimum steroid activity and fewer systemic side effects, such as diabetes, are seen.

Budesonide has a lower risk of side effects due to its high level of first pass metabolism. When the drug is swallowed, it is immediately absorbed by the digestive system, performing as a locally-acting steroid on the irritated and inflamed gastrointestinal tract of IBD sufferers. It then enters the liver through the hepatic portal vein. The liver then metabolizes the drug, forming metabolites that have very weak systemic activity, resulting in a lower incidence of systemic side effects. While budesonide is sometimes the initial steroid given to cats with IBD, cats may also be switched to this drug from prednisolone if that steroid hasn’t been as effective as desired or if difficult to manage side effects have occurred. Veterinarians have used both drugs successfully in their feline IBD patients, so they are both viable options to be considered for your cat.

Essentially, budesonide is inactivated 80-90 percent by the liver. Other corticosteroids influence the biochemical behavior of most tissues of the body, hence the higher incidence of systemic side effects. It’s important to note that liver dysfunction can affect how well the drug is metabolized. As with all steroids, liver function should be closely monitored in patients taking budesonide, and used with caution in patients with decreased liver function. Dr. Wendy C. Brooks states: “Budesonide is a strong corticosteroid, about fifteen times stronger than prednisone. This means that even the minimal amount that does get absorbed can be significant and it appears that the more inflamed the bowel lining is, the more budesonide is absorbed into the body.”

Dosage recommendations for budesonide vary, but the standard is generally 1 mg. per day for cats, regardless of their weight. However, doses may range from .5 mg to 3 mg. per day depending upon the prescribing veterinarian and the cat. For anyone wanting to switch their cat from prednisone/prednisolone to budesonide, a cautious approach is recommended. This is because you are going from a drug with a high systemic effect to one with low systemic availability. Thus, symptoms of withdrawal, such as acute adrenal suppression, may occur. The prednisone/prednisolone may need to be continued on a weaning dose schedule while beginning budesonide. As with all medication changes this is something that should be discussed and coordinated with your veterinarian.

Budesonide can be more expensive than other corticosteroids and it hasn’t been studied extensively in cats with IBD. However, most human trials for its use in treating Crohn’s disease (a form of inflammatory bowel disease) seem to show that budesonide is effective for treating active disease and inducing remission. In addition, its lower risk of systemic side effects is a compelling reason for choosing this drug over other options. Budesonide has been used successfully with cats for a number of years now and many vets are quite comfortable prescribing it for their feline IBD patients.

Update 2016: As a topical steroid that works directly on the intestines when taken orally, budesonide does carry less risk for development of diabetes and complications with heart disease. But we have seen cats develop diabetes with its use, so we want to make sure you understand this is a safer option, but it is still a steroid, and “If used long-term, budesonide also may cause some of the same side effects as corticosteroids.” (MedicineNet: Budesonide in Crohn’s Disease).

As with all medications, it is helpful for some cats and not with others. This may also be due to the fact that budesonide must come into contact with the section of the intestines where there is inflammation, and “As most budesonide is released in the terminal ileum, it will have its best results in Crohn’s disease [IBD] limited to the terminal ileum.” [This is the last section of the intestines just before the colon]. If the inflammation is in a different section or area of the intestines, it may not be effective.  MedicineNet:
http://www.medicinenet.com/crohns_disease/page10.htm

Depo-Medrol / Medrol (Methylprednisolone)
Depo-Medrol is a long-acting steroid shot that is generally administered in a veterinarian’s office.  It lasts between one to six weeks, with an average effectiveness of three to five weeks. It is an option that can be used in lieu of steroid pills and liquids for hard to medicate cats. Depo-Medrol is usually more of a short-term steroid solution than the others discussed in this article. For reasons that are still unclear, this medication often stops working after several months. Additionally, there can be an increased risk of side effects such as diabetes when it is used long-term. Most veterinarians today prefer to use oral forms of short-acting steroids (prednisolone or budesonide) so they can easily change the dosage as needed to moderate drug effectiveness and adverse reactions.

Atopica (Cyclosporine)
Cyclosporine is an immunosuppressant that works by blocking white blood cells from organizing and responding to infection or invasion. Atopica is an oral form of cyclosporine that has been modified for better absorption in the intestinal tract. It is typically used to control feline allergic dermatitis and other immune-system based skin conditions in cats. However, it has also been used successfully in the management of Feline IBD. And like budesonide, it is less likely to cause systemic side effects. The usual dosage of Atopica for cats varies from 2.27 to 5.45 mg. per pound per day. The medication is typically given once per day for 4-6 weeks and then may be tapered to every other day or twice weekly as needed to maintain the therapeutic effect. Atopica is best given on an empty stomach (either one hour before or two hours after a meal) to help facilitate absorption. Generic cyclosporine should be avoided, as its bioavailability has not been tested in dogs or cats.

While Atopica can be effective in treating Feline IBD, there are several cautions for pet owners to be aware of. This medication may increase the risk of infections, including toxoplasmosis, so it is recommended that cats on this drug be kept indoors and not be fed a raw diet. Atopica should not be used in cats with liver disease, as it is removed from the body by the liver and places additional stress on that organ. It is also best avoided in cats with a history of cancer. As stated in the product insert from the manufacturer, prolonged use of Atopica may increase susceptibility to the development of tumors, including lymphoma, due to the suppression of the immune system.

Side Effects of Steroids
You may have taken steroids yourself for a medical condition or know someone else who has. If so, you may be worried about the potential side effects of these drugs, including weight gain, water retention, and mood changes. While side effects can occur in cats that are given steroids, especially for long periods of time, the incidence of these problems is lower than what is seen in either humans or dogs. That said there are issues that may arise in some cats.

Both short-term and long-term side effects can occur with steroid usage. Some of the possible short-term side effects include:

• Increased hunger
• Increased thirst and urination
• Loss of energy
• Behavior changes
• Development or worsening of infections (especially of the skin)
• Vomiting or nausea (less common)
• Occasionally personality changes (steroids can change behavior, but this is a relatively rare side effect).

The increased hunger that may be seen in cats taking steroids is often welcomed by their owners, as cats with IBD often eat less than they used to. This is especially helpful when working to change to a novel protein diet or to higher quality food sources (e.g. from dry food to canned, or to a raw food diet or home-cooked diet). However, this side effect is not seen in all cats and may also be temporary. In addition, some cats may have a reduced appetite when taking steroids, but this is less commonly seen.

The other short-term side effects are things to watch out for and to share with your veterinarian if noticed. If the side effects are unmanageable, the steroid dosage may need to be adjusted or an alternate steroid or another drug may need to be used.

When steroids are used for more than three or four months, particularly at higher doses, additional side effects may be encountered. The most commonly seen long-term side effects include:

• Urinary tract infections (UTI – occurs in up to 30% of patients)
• Development of thin skin, blackheads, hard plaque spots on the skin (calcinosis cutis), or a poor or thin coat
• Poor wound healing ability
• Obesity (due to increased hunger)
• Muscle weakness
• Susceptibility to infections
• Changes in liver function
• Predisposition to diabetes and Cushing’s disease

To reduce the risk of any of the above side effects, it’s best to avoid using steroids on a daily basis. Steroids are present in the body about thirty-six hours after administration, so if the steroid is given daily, some of the previous day’s dose is still present. Most steroid protocols require daily use only during the initial treatment phase and then the dosage is often dropped down to every other day.

Since the cat’s adrenal glands function primarily in the morning hours, it’s best to give steroid medications in the evening, as the dose will begin to wear off as the adrenal glands are ready to kick in. The preferred way to give steroids on a long-term basis is to administer them every other evening. It’s important not to abruptly discontinue steroid usage, as this can cause serious or life-threatening consequences. The dose must be tapered under the supervision of your veterinarian.

References:
Inflammatory Bowel Disease in Cats – VCA Animal Hospitals
Feline Inflammatory Bowel Disease – Max’s House
Inflammatory Bowel Disease in Small Animals – The Merck Veterinary Manual.
Steroid Treatment – Long-Term Effects in Cats – VCA Animal Hospitals
Corticosteroids – Peteducation.com
Prednisone and Other Corticosteroids – The Mayo Clinic
Prednisolone for Veterinary Use – Wedgewood Pharmacy
Prednisolone and Prednisone for Dogs and Cats – Wedgewood Pharmacy
Bioavailability and Activity of Prednisone and Prednisolone in the Feline Patient – Veterinary Dermatology
Budesonide (Entocort EC, Entocord) – The Pet Pharmacy
Budesonide for Cats – Vetinfo.com
Wedgewood Pharmacy (general reference for medication formats)
Entocort EC Product Monograph –  Astra Zeneca
A Guide to Depo Medrol for Dogs and Cats – The Anti-Inflammatory – Pet Care Rx
Cyclosporine – The Pet Pharmacy
Atopica for Cats – Official Product Site (Novartis)
Atopica Use in Cats – eHow

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